The present invention relates to a system and a process for detecting, assessing, grading and diagnosing heart conditions in human beings. In accordance with the system and process of the present invention, a spectral phonocardiogram signal and a corresponding electrocardiogram signal are displayed simultaneously, preferably in a synchronized relationship, to facilitate the detection, assessment, grading and diagnosis of a heart condition.
U.S. Pat. Nos. 4,967,760 and 5,012,815, both to Bennett et al., illustrate dynamic spectral phonocardiogram (DSP) systems for generating a spectral phonocardiogram which summarizes time dependent changes in the heart sounds through a heart cycle. The systems are based on the projection of spectral surfaces of the Fourier transform of heart sounds as a function of time. They have been used to screen people for heart disease.
U.S. Pat. No. 4,905,706 to Duff et al. illustrates a similar method and apparatus for detecting coronary artery disease. The Duff et al. system records and analyzes that portion of the phonocardiogram lying between about 100 to 600 Hz. An electrocardiogram is recorded and examined in order to pinpoint the diastolic window of PCG data. This window of data is subjected to autocorrelation analysis and spectral analysis to yield a partial correlation coefficient index and a power density index. A linear combination of these two indices is then used to generate yet another index, termed a Cardiac Screening Index, which is indicative of the presence or absence of coronary artery disease.
The principal disadvantages associated with these systems are that they are limited in scope to dynamic spectral phonocardiograms without any synchronization, which severely limits their clinical utility and application, and to a 2-d phonocardiogram system with electrocardiogram (ECG) which is also severely limited in diagnostic utility because it omits the critical parameters of full frequency and amplitude distribution of heart spectra as a function of time. The Bennett et al. systems, in particular, confine production of spectral patterns to Fast Fourier Transform functions and omit other forms of mathematical approaches which are capable of providing a spectral pattern with adequate resolution for diagnostic purposes.
Bennett et al.'s DSP system is further limited by its time resolution in distinguishing first heart sound (systolic function) from second heart sound (diastolic function) and the critical timing of murmur spectra which has a direct bearing on the valvular source of the murmur. This deficiency is especially evident when the murmur is holosystolic, i.e., it appears across the full timing range of the first and second heart sounds, thus totally blotting out any pattern recognition capability for the human eye to discern the systolic or diastolic timing of important murmur spectra.
Accordingly, it is an object of the present invention to provide a system and process for detecting, assessing the cardiac timing of, grading, and diagnosing a variety of valvular and arrythmia conditions.
It is a further object of the present invention to provide a system and a process as above which provides a total picture for enabling rapid assessment of the overall integrity of a heart.
It is still a further object of the present invention to provide a system and a process as above capable of providing automated computer diagnosis of the probable nature of the condition of a heart.
Still other objects and advantages of the present invention will become more apparent from the following description and drawings wherein like reference numerals depict like elements.